Lead-press



(No Model.)

H. B. COBB. LEAD PRESS.

Patented Mar. 6, 1894.

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UNITED STATES PATENT OFFICE.

HENRY l5. COBB, OF \VILMINGTON, DELAXVARE.

LEAD-PRESS.

SPECIFICATION forming part of Letters Patent No. 515,951, dated March 6, 1894.

Application filed July 30, 1892.

T0 aZZ whom it may concern:

Be itknown that I, HENRY B. COBB, a citizen of the United States, residing at lVilmington, in the county of New Castle and State of Delaware, have invented a new and usetul Improvement in Lead-Presses, of which the following is a specification.

My invention relates to an improvement in the class of machines for use in forming tubing from plastic material capable of being subsequently hardened, such as molten lead, (from the use of which the machine is named) plastic rubber, and the like.

A machine of the class to which my improvement relates involves, as its generally stated usual construction, a frame supporting a rammer, (either stationary or vertically reciprocating,) a piston, usually actuated by hydraulic pressure, a chamber for containing the charge of material (as lead) and in vertical line with the rammer (which, if movable, is operated to work in and out of the chamher, or, if stationary the chamber is reciprocable with relation to it) and a die-chamber containing the tube-forming die and extending across the lead-chamber with which it communicates.

The object of my improvement is to provide a construction of press of the aforesaid class whereby its product may be turned out much more rapidly than by any other known construction thereof, and whereby the enormous pressure employed in evacuating the leadchamber of its contents to form the tubing may be exerted directly from the lead-chamber against the die crossing its outlet-opening, without bending and injuring the die; and it is also my object to enable the use to be dispensed with of the quite commonly provided so-called bridge covering the communicating opening between the die-chamber and lead-chamber to induce distribution of the pressure about the die, thereby to prevent injury of the latter by the enormous pressure, but which bridge tends to obstruct, and therefore to retard, the operation of the machine and thus reduces its capacity. I accomplish my objects by inclining the diechamber downward from the side of the leadchamber discharge-outlet opposite the side thereof adjacent to the die-chamber outlet to,

or nearly to, or beyond, the opposite side of Serial No. 441,672 (No model.)

the said discharge-outlet at the base of the diechamber, whereby the die below such outlet may be exposed on its upper side to the full diameter of the lead-chamber discharge-outlet while being solidly supported underneath throughout such diameter, and whereby, furthermore, the deflection of the vertical pressure immediately to a right-angle in the diechamber, as hitherto in other constructions, is supplanted by a gradual, or obtuse-angle deflection in the die-chamber toward its discharge-outlet, which very materially facilitates and enhances the turning out of the product while greatly diminishing the strain on the machine.

In the accompanying drawings, Figure l is a view in sectional elevation showing a lead press provided with my improvement; and Figs. 2 and 3 are top views, respectively, of different details of my improvement and enlarged over the scale presented in Fig. 1.

Except as to the peculiar construction of the die-chamber and, preferably also, of the die therein, the machine ma involve any suitable or usual construction of lead-press.

I have designed the press with my improve ment for use in the manufacture of tubing from any suitable material, as hereinbefore stated,but particularly from soft rubber and from lead; and when used for producing load tubing, then more particularly for manufacturing lead-coated electric conducting wire or cable insulated with rubber, or a rubber compound, and preferably also with parafline, or the like, interposed between the lead and rubber. I therefore, in the drawings, show my improved machine as applied to the manufacture of the lead-coated wire or cable referred to, and hereinafter describe its operation as applied to that particular purpose.

A denotes the supporting pillars carrying on their upper ends the head 13, from which depends a stationary rammer 0.

D is the head on the vertically reciprocating hydraulic piston (not shown) and carrying the die chamber E formed in the bloclzF to extend transversely across the machine. On the block F is supported the lead or supply-chamber G, which should be, as shown, of uniform diameter throughout its interior, and which leads at its base into an opening *1, in vertical line with it, through the top of the block F, and the sides of which should converge downwardly, as shown, to the entrance of the opening into the die-chamber. The lead-chamber G and head D may, as usual, he bolted together through their respective flanges, as shown. In the hollow block F, the die-chamber E is formed with the adjacent ends of hollow die-supporting sleeves F and F open at their opposite ends and there coinciding with threaded openings in the block F for hollow die-adjusting setscrews, 1) and p; and the opening r in the base of the block F continues between the sleeves F and F into the die-chamber. The sleeve F, shown as cylindrical, is beveled on its inner end to form about the core-tube I, hereinafter described, an inclined shoulder or flange, which affords one wall (the farthest from the outlet for the product) of the die-- chamber, the shoulder being at, or about at, such an angle of downward inclination that it will form a continuation of the degree of incline of the adjacent side of the opening 1', and continue to the base of the die-chamber about to, and preferably beyond, as shown, the vertical plane of the base of the opposite side of the opening 1". In the block F is the core-tube I held against backward displacement by the set-screw p, and projecting at its forward tapering end w beyond the inclined rear wall of the die-chamber afforded by the forward end of the sleeve F in line with the opening through a die K in the sleeve F and which is held by the set-screw 19. For a purpose hereinafter described I extend from the top of the sleeve F a finger n at the base of the outlet 4" over the top of the adjacent end-portion of the core-tube I. As will thus be seen, the inner wall 0 of the die-chamber, formed with the inclined shoulder about the core-tube and afforded by the beveled end of the sleeve F, inclines downward at an angle of forty-five degrees, or thereabout toward the outlet for the product through the die K and forms along its baseportion a solid supporting base for the die nearly throughout its full length, at least extending sufficien tly far to present a solid bearing for the core-tube beyond the area of pressure exerted thereon at the top through the base of the lead-chamber.

While it is preferred to form the core-tube and its supporting sleeve as two separate parts, as represented, they may be in one piece, when the inclined end of the sleeve portion would afford, practically, an inclined flange or shoulder surrounding the core-tube.

The sleeve, as such,performs no particular function; and its separate construction is purely a matter of convenience in providing the inclined abutment, shoulder or flange at its inner end, which, however, could be as well integral with the block F, except for the difficulty in so constructing it.

To operate my improved machine for producing lead-coated cable L, the proceeding is as follows: It should be stated that for the manufacture of the cable L, I provide a bent guide-tube M, connected with the inlet-end of the set-screw p, to direct into and through the core-tube I the rubber-covered cable L to be coated with the lead, and a paraflineholder N, supported on the tube M to feed into the latter, around the rubber on the wire, the molten para'ffine. The chamber G being charged with molten lead, which enters also and'fills the space in the die-chamber E, and the cable L having been inserted into the machine sufficiently far to extend past the die K, the hydraulic piston is actuated to raise the parts supported by it. Thus the lead in the chamber G is forced with great pressure against the ram mer O, and discharged about the tapering end of the core-tube I through the die K around the cable L, which is drawn, by the pressure, through the. machine and coated with a lead-shield, thus emerging from the discharge-outlet as the paraffined lead-covered rubber-insulated wire L. As will be seen, the vertical pressure of the rammer against the molten lead in the chamber G is largely resisted by the inclined wall 0 of the die-chamber, on which the pressure is much more gradually deflected toward the outlet and therefore the less ilnpedes the discharge, than in other machines wherein the resistance to the pressure is entirely at a right-angle to the direction thereof. Furthermore, the core-tube I, though exposed to the full force of the lead-chamber pressure, can not be bent and thereby deflected from its required straight position with relation to the die K, since it bears against a solid foundation below the area of the directly exert-ed pressure in the leadchamber.

The purpose of the inclined shoulder afforded by the inner end of the sleeve F will be understood to be twofold: It deflects the material in forming the tubingand equalizes the pressure about the die K; and it affords a perfect support for the core-tube I against the downward pressure of the material in the supply-chamber G under the great force of the hydraulic ram.

Partly to distribute the pressure the more about the tapering end-portion of the coretube 1, and partly to equalize continuously the supply of the molten lead, I extend the deflecting pointed fingernin the manner described, from the top of the die-sleeve F Too great stress cannot be laid on the importance of the advantage of my improvement in enablinga bridge to be dispensed with. A bridge greatly obstructs the flow of the material and requires that the die-block F be made in halves in order to give the diechamber E the proper shape to form the tubing. By my improvement the block F may be originally solid and bored from the righthand end to the point denoted at y, where the diameter of the bore is reduced, forming a shoulder which affords a firm support for the sleeve F and affording, with the die K,

the front side of the die-chamber, the rear side thereof being formed by the sleeve F and core-tube I. According to my improved construction the die-chamber is perfectly and conveniently formed by inserting the die K and sleeve F into one end of the bore in the block F, and the sleeve F and core-tube I into the other end thereof, thereby producing the die-chamber with much more exactness and at much less cost than by the usual method of carrying out the desired shape with a cold chisel.

A lead or analogous press may be variously constructed diiferently from that described and still be adapted to have advantageously employed with it my improvement, the essential feature of which is to be understood as consisting in the inner wall in the die-chamber inclined downward from, or from near, the base of the lead-chamber at its inner side or side farthest from the die-chamber outlet, toward that outlet. Hence I do not wish to be understood as in any way intending to limit the use of my improvement to a particular construction of the press.

For the sake of brevity I designate the press provided with my improvement as a leadpress, in the appended claims, but intend to have the claims include such a press whatever be the material capable of employment therein to produce tubing or insulated wire by its operation.

What I claim as new, and desire to secure by Letters Patent, is-- 1. In a leadpress, a die-chamber into which the supply-chamber opens freely and having its inner wall inclined downward from the supply-chamber outlet above the plane of the core-tube to the base of the die-chamber near its discharge-outlet, substantially as described.

2. A lead press core-tube I for a die-chamber E, said core-tube having an inclined shoulder encircling it and adapted to be adjusted in said die-chamber and form, with the wall thereof, the inclined rear wall 0 extending downward from the supply-chamber outlet above the plane of the core-tube to the base of the die-chamber near its discharge-outlet, substantially as and for the purpose set forth.

3. In a lead-press, a die-chamberinto which the supply-chamber opens through an unobstructed passage, said die-chamber containing a core-tube and having its inner wall formed with a downward inclined shoulder encircling the core-tube, and projecting below the same forward beyond the vertical plane of the front side of said unobstructed passage, substantially as described.

at. In a lead-press, the combination with the supply chamber and rammer, of a die-chamber into which the supply-chamber opens and containing the diesleeve F supporting the die K, and core-tube I surrounded in the diechamber by a sleeve F extending across the open base of the supply-chamber, inclined at its inner end to extend from the rear upper portion of the die-chamber to the base thereof adjacent to the 'discharge-outlet and form the die-chamber wall 0, substantially as described.

5. In a lead-press, the combination with the supply-chamber and rammer of a die-chamber into which the supply-chamber opens and containing a die-sleeve F, a die K in the said die-sleeve and provided with a finger n, a die-sleeve F in the die-chamber, having its innerend inclined and forming the die-chamberwall O, and a core-tube Lin the die-sleeve F, extending across the open base of the supply-chamber under the said finger, substantially as described.

6. In a lead-press, the combination with the supply-chamber and rammer of a block F for the die-chamber and having the hollow setscrews 1) and p in its opposite ends and an inlet-opening r in its upper side at the base of the supply-chamber, a die-sleeve F in the die-chamber containing the die K provided with a finger at, and a die-sleeveF in the diechamber, having the inclined inner end forming the wall 0, and a core-tube I, in the diesleeve F, extending across the opening a under the said finger, substantially as described.

M. J. Fnosr, M. E. WINN. 

